Radar – is an acronym for Radio, Detection and Ranging and uses electromagnetic energy. The equipment is mounted in all HWP cars and can be used either stationary or mobile. The unit operates from the police vehicles internal power and consists of an antennae head, computer section and remote unit. The instrument’s range depends on terrain, operating line of sight.
The energy emitted by the radar unit hits the target vehicle and is returned to radar antenna. If there is relative motion between the target and radar antenna the frequency changes (doppler effect); the computer section measuring the frequency shift and calculating the relative velocity displayed as a speed measurement.
Lidar devices (hand held laser speed detection)
Lidar – is an acronym for Light, Detection and Ranging which uses laser based infra red light. Police use lidar units in both metropolitan & country locations. Most police motor cycles are equipped with a lidar instrument and those HWP sections without cycles; still have access to the technology to assist with for speed enforcement.
These units are used in the stationary mode and are well suited to multi-lane roads with higher traffic volumes. They are also ideally suited for enforcement in the vicinity of schools. A lidar is powered by a battery pack or by being plugged into a power socket fitted to police cycles. The units can be hand held, mounted on a tripod or monopod. The steadier the platform the greater the range, however, for operational purposes speeds are generally detected in a 600 metre range.
The lidar does not measure speed – it measures time of flight of each reflected pulse of energy from the target and the known time between pulses, converting it into a speed measurement.
Speed cameras were first introduced in NSW in 1991. The new generation Traffipax equipment is now vehicle mounted. A speed camera basically consists of a camera data recorder fitted to a conventional slant radar unit. This system can be modified to digital imaging in the future.
Speed cameras are dispersed throughout NSW and are operated in locations with a known crash or speeding history. They are used in stationary mode and are suitable for use in moderate traffic areas with multi-lanes. The vehicle mounted speed cameras can monitor both directions of travel simultaneously, day or night and in all weather conditions.